Former Northern Ireland secretary Lord Mandelson has told MPs he has no regrets over his involvement in a contentious government process to deal with on-the-run republicans.
The Labour peer insisted he approached the fugitives issue in a "sensible, proportionate and principled way".
The politician was giving evidence to the Northern Ireland Affairs Committee inquiry into a scheme formulated by the last Labour government at the request of Sinn Fein that saw about 200 letters sent to so-called on-the-runs (OTRs) assuring them they were not being actively pursued by the UK authorities.
The probe was triggered by the high-profile case of John Downey, who walked free from the Old Bailey earlier this year when his prosecution for the murders of four soldiers in the 1982 IRA Hyde Park bomb was halted by a judge when it emerged he had been sent one of the letters in error.
Lord Mandelson was not Northern Ireland secretary when the mistakes around the Downey case were made but he was in office when the process effectively started operating in 2000.
He told the committee he was satisfied how he had acted in trying to address the issue of on-the-runs.
"No, I do not have regret in trying to find a way through the problem of OTRs, which in my view I did in a sensible, proportionate and principled way," he said.
The peer said in his time the way letters were sent was more of a "sketchy process" rather than the more substantive administrative scheme it developed into in later years.
Co Donegal man Downey, 62, who denied involvement in the bombing, was wrongly issued with a letter because Government officials in the Northern Ireland Office (NIO) were not told by police in Northern Ireland that he was being actively sought by the Met for the Hyde Park outrage.
The Old Bailey judge put a stay on his prosecution as he deemed his arrest at Gatwick airport in 2013 constituted an abuse of process.
Household Cavalry Lieutenant Anthony "Denis" Daly, 23, died in the explosion in Hyde Park on July 20 1982 alongside Trooper Simon Tipper, 19, Lance Corporal Jeffrey Young, 19, and 36-year-old Squadron Quartermaster Corporal Roy Bright.
A judge-led review of the wider letters scheme ordered by Prime Minister David Cameron and published in the summer found it was systematically flawed in operation but not unlawful in principle.
But Lady Justice Hallett, who conducted the probe, said a "catastrophic" error had been made in the Downey case.
Lord Mandelson acknowledged that more steps could have been taken to prevent that mistake.
"Should the whole process have been undertaken with more care, more manpower, more examination and re-examination, proper consultation between different police forces, ideally yes, because one mistake is one too many," he said.
In Lord Mandelson's time in office, nine letters were sent to on-the-runs, Royal Prerogatives of Mercy were given to some other fugitive republicans and extradition proceedings against others were dropped.
He insisted all those actions could be justified as they only impacted on individuals who were either not wanted or who had already been convicted and imprisoned.
The peer said he ruled out legislating for an amnesty for other OTRs as it would have prompted outrage among victims and the wider community.
Lord Mandelson said Sinn Fein were not happy with the letter scheme, considering it "sub-optimal" as it did not address the OTRs who remained wanted.
He noted the case of Rita O'Hare and revealed that his predecessor in office, the late Mo Mowlam, had stressed to him the urgency of dealing with her case.
Ms O'Hare, Sinn Fein's representative to the United States, is one of the most high-profile fugitive republicans, having skipped bail to the Irish Republic in 1972 after her arrest in connection with the attempted murder of a soldier.
Lord Mandelson told the committee that the Government could not accede to Sinn Fein's demand to get her case resolved as the opinion of the then UK Attorney General made it clear she could not be allowed to return without facing due process.
He said Sinn Fein may not have explicitly asked for an amnesty but that was what the party wanted. The peer said Sinn Fein were essentially asking him to wave a "magic wand" at the problem.
Four years after the then Labour MP left office, the Government did attempt to legislate on the issue but the bill was ultimately dropped when Sinn Fein withdrew its support.
He told the committee: "Those letters were not a solution, we have never found a solution to OTRs.
"We have followed a piecemeal and selective procedure or scheme, we have never found a complete solution to the issue of OTRs."
During a two-hour session in front of committee members, Lord Mandelson also addressed the perception held in some republican quarters that he was more inclined to the unionist parties in Northern Ireland.
"I think at the end of the day I did right by everyone, including incidentally by republicans and nationalists, even though they may not be the first to acknowledge that now," he said.
The peer said he always strove to maintain a balance in all his dealings in the region. But he went on to claim that both the Irish and US government lobbied for a pro-nationalist/republican agenda during peace process talks so, as a consequence, he often found himself having to put the counter position.
"I wasn't the number one pin-up in Dublin and I think there were times in Washington when I think they wished I wasn't there, but it's not a question of being on one person's side or the other," he said.
He added: "I would find myself sometimes saying to my opposite number, (then Irish foreign affairs minister) Brian Cowen or whoever it was in Dublin, or the emissary whoever it was at that time for Bill Clinton, 'Look, yes I know the republicans want this or the nationalists want the other and I would like to accommodate them, I would like to find a compromise where they were satisfied, but you do have to consider those who are sitting on the other side of the table'.
"I saw it as my job to rectify any imbalance that was created by two governments weighing in on side side of the discussion."
He noted an occasion he had a private dinner with Mr Cowen in Hillsborough Castle.
"He said to me 'My job is to deliver the republicans and nationalists and your job is to clear the unionists out of the way'."
The peer added: "His view was I was there to persuade unionists to whatever was agreed and his job was to deliver republicans and nationalists.
"That is not what I thought was the right characterisation of the situation, or of my role."
A number of committee members asked Lord Mandelson to prevail upon his long-time friend, former prime minister Tony Blair to give evidence to the committee.
Chairman Laurence Robertson said while Mr Blair had not refused to appear, he had informed members he had been unable to find a date in his diary.
"I am sure if he were able to come he would," replied Lord Mandelson.
"I have never known any circumstances where Mr Blair didn't have something of value to add to a discussion."